An electric rotating machine is a machine for rotating a rotor located in an opposite relation with a stator. The rotor and stator are heat generation sources due to iron loss or copper loss, etc. In order to suppress the temperature elevation in the rotating machine, the machine is cooled with a coolant. Generally, gaseous coolants such as hydrogen gas or air are widely used as the coolant. When air is used as the coolant, ducts that penetrate the radial direction or the axial direction are disposed in the rotor and stator, the ducts. A fan for compressing air is disposed at the end of the rotating shaft; the rotor and the stator are cooled by causing the air to pass through the ducts.
A technology for cooling the rotor and stator is disclosed in Japanese Patent Laid-open print 10-150740, Japanese Patent Laid-open print 2000-125511. According to the technology, air streams merge in front of the fan disposed to the end of the rotor shaft, after the air passes through the ducts that penetrate the rotor and stator. The air stream is energized by the rotation of the fan and again distributed. One of the distributed cooling air streams is guided to the stator, and the other is guided to the rotor.
In the technology disclosed in Japanese Patent Laid-open print 10-150740, the merged air streams are cooled with a relatively large cooler. After the air is cooled in the cooler, it is distributed to the stator and the rotor.
In the technology disclosed in Japanese Patent Laid-open 2000-125511, the merged air streams are distributed into two streams, and then the streams are guided to different coolers to be cooled separately. One of the air streams is guided to the stator and the end of the windings, and the other to the rotor.